Conveyors that carry products in a hanging manner are commonly known in textile factories, e.g. for sewing shirts, wherein different pieces of cloth hangs in a product carrier, which travels on a rail to a workstation, where all or part of the pieces are to be sewn together. The product carrier consists of two wheels held together by an axis. The wheels are intended to roll on the support surfaces of the main rail and are guided in the sideway direction by a centrally positioned guide rail.
The guide rail may be integrated in the main rail, which gives a cost-effective straight rail. However, when a product carrier is to leave or enter the main rail, a switch adapted to divert the product carrier to or from the main rail must be used. With the guide rail integrated in the main rail, the main rail must be cut off in order to be able to insert a complete switch module in the main rail. This gives an inflexible solution which is difficult to rebuild or change.
It is also known to use a separate guide rail being a straight beam that is mounted to the main rail. In this way, the main rail does not have to be cut in order to insert a switch unit. In this solution, the guide rail is cut off in order to insert a switch unit. This provides a more flexible solution, which still is somewhat difficult to rebuild. Such a solution is known from WO 9854074.
By providing guide rails in a modular design, an even more flexible solution is provided, in which one or a few guide rail elements can be easily removed from the main rail in order to provide space for a switch element. Each guide rail element is positioned in predefined mounting positions, having mounting holes for the attachment of the guide rail elements. Preferably, the switch element is also of a modular design. Such a solution is known from WO 2007018462, which is hereby incorporated as reference.
Depending on the use of the product carriers, i.e. the goods carried by the product carriers, there may be a need to separate the product carriers from each other, such that they do not bump in to each other or such that the goods carried by the product carriers do not bump in to each other. If the products are soft, they may entangle or get caught in each other if they touch each other, and if the products are larger and harder, they may deform or damage each other if they are allowed to run into each other.
Different solutions to this problem are known. In one solution, the product carriers are provided with an integrated spacer that will give a defined distance between each product carrier. The spacers will bear on each other and will thus provide a defined distance between each product carrier without the need of specific stop elements. The product carriers may also be provided with a protective cover which holds the products apart.
It is also possible to introduce different stop elements in the conveyor. Such stop elements are commonly used before a work station in order to release a product carrier when the work station is ready to receive a new product carrier. The stop element is controlled by a control unit of the conveyor system. It is however impractical to provide a plurality of active stop elements in order to allow the product carriers to queue with a predefined distance apart.
These solutions work fine in some systems, but there are still room for improvements.